Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Mimicking the ingenuity of nature

03.05.2016

A clean, climate-friendly energy source that is virtually inexhaustible: This is the promise artificial photosynthesis holds. Chemists from the University of Würzburg have now got one step closer to reaching this goal. The scientists present their work in the journal Nature Chemistry.

Nature shows how to do it: Photosynthesis is a process used by plants to create energy-rich organic compounds, usually in the form of carbohydrates, and oxygen (O2) from carbon dioxide (CO2) and water (H2O) driven by light.


Three ruthenium atoms linked via specially shaped organic bonds make sure that the photosystem works more efficiently than its predecessors.

Graphic: Valentin Kunz & Marcus Schulze

If we succeeded in mimicking this process on a large scale, numerous problems of humanity would probably be solved. Artificial photosynthesis could supply the Earth with fuels of high energy density such as hydrogen, methane or methanol while reducing the amount of carbon dioxide in our atmosphere and slowing down climate change.

Developing the necessary efficient catalysts and associated dyes is a focal area of research at the Chair of Professor Frank Würthner at the University of Würzburg's Institute of Organic Chemistry. Two of Professor Würthner's doctoral students, Marcus Schulze and Valentin Kunz, have recently reported a partial success in this regard. They present the results of their research work in the current issue of the journal Nature Chemistry.

Improving an artificial photosystem

"In nature, the so-called photosystem II is a central component of the photosynthesis process", explains Marcus Schulze. It is a protein complex with a catalytically active centre consisting of multiple metal atoms. They have to work together to split water into its two elementary constituents, a process taking place in two spatially separated electrochemical half reactions. It is already possible to mimic these two reactions in the laboratory. But: "Hydrogen production already works quite well. The water oxidation to oxygen, however, needs to be accelerated so that the balance of the individual half reactions matches better," says Schulze.

Scientists still frequently use the rare noble metal ruthenium as a catalyst for artificial photosynthesis. Basically, the artificial system works with similar efficiency as its natural counterpart. However, the catalyst tends to decompose itself relatively quickly. This is where the chemists of Würzburg leapt to action: "We incorporated the ruthenium atoms into special supramolecular structures which slow down the destruction and enable a kind of 'self-healing process'," Valentin Kunz explains.

Two years of lab work

This structure is similar to a ring in which three ruthenium atoms are interconnected using three so-called ligands which are specially shaped organic compounds. Custom-tailored binding sites make sure that the metal centres and ligands fit like key and lock. What sounds comparably easy took two years of non-stop meticulous working in the laboratory. "You successively turn different screws and see what happens," Kunz describes their approach.

The result is a "cyclic self-composing system of defined individual blocks" as the two chemists explain. Its benefit in "synthetic terms" is its simple structure and ease of production along with the fact that the blocks automatically assemble to form the desired structure without requiring major technical effort. This property makes it better suited for potential applications than previous systems.

The next steps

The chemists are pleased to note that the water oxidation catalyst they developed is also more efficient, although they cannot yet explain why that is so. These explanations might be delivered in the near future by the experts in theoretical chemistry with whom Frank Würthner's chair is cooperating closely. Roland Mitrić, head of the Chair of Theoretical Chemistry at the University of Würzburg, and his co-worker Merle Röhr are already looking for an answer to this question by developing formulas and algorithms.

Even though the system of the two junior scientists is better than its predecessors: "We still have a long way to go until the process is ready for the market," explains Marcus Schulze. And: "What we are doing is fundamental research," Valentin Kunz adds. The next steps have already been planned: Firstly, the chemists want to study further changes at the catalyst's structure and their impact on the function. Secondly, they want to link it to dyes so that the reaction becomes photocatalytic, which means the reaction will work with light.

The joint project Soltech

Marcus Schulze and Valentin Kunz's research was performed within the scope of the Bavaria-wide joint project Soltech (Solar Technologies Go Hybrid). Launched in 2012, the Free State of Bavaria funds new concepts to convert solar energy into electricity and non-fossil fuels. So-called key labs in the following universities are involved in the project: University of Bayreuth, University Erlangen-Nuremberg, LMU Munich, TU Munich and the University of Würzburg.

The Würzburg key lab is located at the Center for Nanosystems Chemistry founded in 2010 at Professor Frank Würthner's initiative. His research team has been working on selectively organising small organic molecules to form larger assemblies that absorb sunlight and transport it to electrodes to be converted into electric power. Another goal of the Würzburg key lab is to develop artificial chloroplasts that use light energy to generate fuels similar to a plant cell.

The joint project also includes other participants from Würzburg such as the work groups of Professors Tobias Brixner, Christoph Lambert, Florian Beuerle, Roland Mitrić and Todd Marder from chemistry as well as the teams of Vladimir Dyakonov and Jens Pflaum in physics.

A supramolecular ruthenium macrocycle with high catalytic activity for water oxidation that mechanistically mimics photosystem II; Marcus Schulze, Valentin Kunz, Peter D. Frischmann and Frank Würthner; Nature Chemistry, DOI: 10.1038/NCHEM.2503

Contact

Prof. Dr. Frank Würthner, Institute of Organic Chemistry of the University of Würzburg, Phone: +49 931 31-85340, wuerthner@chemie.uni-wuerzburg.de

Weitere Informationen:

http://www.nanosystems-chemistry.uni-wuerzburg.de/home/ Center for Nanosystems Chemistry
http://www.soltech-go-hybrid.de/ Soltech joint project

Gunnar Bartsch | idw - Informationsdienst Wissenschaft

More articles from Life Sciences:

nachricht What happens in the cell nucleus after fertilization
06.12.2016 | Helmholtz Zentrum München - Deutsches Forschungszentrum für Gesundheit und Umwelt

nachricht Researchers uncover protein-based “cancer signature”
05.12.2016 | Universität Basel

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Significantly more productivity in USP lasers

In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.

Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...

Im Focus: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

Simple processing technique could cut cost of organic PV and wearable electronics

06.12.2016 | Materials Sciences

3-D printed kidney phantoms aid nuclear medicine dosing calibration

06.12.2016 | Medical Engineering

Robot on demand: Mobile machining of aircraft components with high precision

06.12.2016 | Power and Electrical Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>